Ravi Thomas

The Use of Two-Stage Molteno Implants in Developmental Glaucoma

Developmental glaucoma, which cannot be controlled by conventional techniques, poses a difficult problem. Twenty-three eyes of 18 patients with developmental glaucoma underwent a two-stage implantation of the double template Molteno valve with follow-up between 12 and 84 months. The final pressure with medication was less than 21 mm Hg in 78% of the cases. These results were obtained in four out of four eyes with primary congenital glaucoma, six out of eight eyes with secondary congenital glaucoma, and eight of 11 eyes in which glaucoma followed surgery for congenital cataract. We feel that two-stage implantation of Molteno valves has a place in the management of difficult developmental glaucomas and is a reasonable early option when glaucoma occurs following surgery for congenital cataract.

Role of frequency doubling perimetry in detecting neuro-ophthalmic visual field defects.

PURPOSEnTo report the ability of frequency doubling perimetry to detect neuro-ophthalmic field defects, characterize them as hemianopic or quadrantanopic, and differentiate glaucomatous from other neuro-ophthalmic field defects.nnnMETHODSnSixty eyes of 30 normal subjects, 50 eyes of 29 patients with glaucomatous defects, and 138 eyes of 103 patients with typical neuro-ophthalmic field defects underwent automated perimetry using the Swedish Interactive Threshold Algorithm and frequency doubling perimetry. The sensitivity and specificity for identification of a field defect (frequency doubling perimetry 20-5 and 20-1 screening tests), or to characterize hemianopia/quadrantanopia (full threshold test) were determined. Ability to discriminate glaucomatous defects was determined by comparing frequency doubling perimetry full threshold test in glaucoma to pooled results of normal and neuro-ophthalmic groups.nnnRESULTSnOn frequency doubling perimetry, a single point depressed to less than 1% probability had a sensitivity of 97.1% (20-5 test) and 95.7% (20-1 test) for detecting a neuro-ophthalmic visual field defect. The corresponding specificities were 95% using pooled results in normal subjects and patients with glaucoma and other neuro-ophthalmic field defects. In 20-5 screening a single abnormal point depressed to less than 2% probability level had a sensitivity of 98.6% (specificity 85%). Two abnormal points in the 20-1 screening depressed to less than 1% probability level had a specificity of 100% (sensitivity 84.8%). In frequency doubling perimetry full threshold, sensitivity and specificity for detection of hemianopia were 86.8% and 83.2%; for quadrantanopia they were 79.2% and 38.6%. The sensitivity and specificity for categorizing a defect as glaucomatous were 86% and 74.7%.nnnCONCLUSIONSnFrequency doubling perimetry is a sensitive and specific test for detecting neuro-ophthalmic field defects. The presence of two abnormal points (20-1 screening program) rules in the presence of a field defect. A normal 20-5 program (absence of a single abnormal point) almost rules out a defect. Frequency doubling perimetry could not accurately categorize hemianopic, quadrantanopic, or glaucomatous defects.

Posterior capsule rupture after blunt trauma.

Abstract Two patients had rupture of the posterior lens capsule caused by blunt trauma. In both, the typical fibrosed edges of the posterior capsule breaks were clearly visible and could be documented preoperatively.

Role of frequency doubling technology perimetry in screening of diabetic retinopathy.

PURPOSEnTo study the ability of frequency-doubling technology perimetry (FDT) to detect sight-threatening diabetic retinopathy.nnnMETHODnFifty-eight eyes of fifty-eight patients with established diagnosis of diabetes mellitus with diabetic retinopathy, fifty-five eyes of fifty-five diabetic patients without retinopathy and forty-one eyes of forty-one normals underwent FDT and dilated stereo-biomicroscopic fundus examination. The sensitivity and specificity of FDT in identification of sight-threatening retinopathy (severe and very severe nonproliferative diabetic retinopathy and proliferative diabetic retinopathy) and clinically significant macular edema (CSME) were determined.nnnRESULTSnFor the detection of sight-threatening retinopathy, two abnormal adjacent points depressed to any level on the 20-1 screening program had a sensitivity of 90.5% and specificity of 97.6%. At (assuming a) 10% prevalence of sight-threatening retinopathy in a diabetic clinic, two abnormal adjacent points anywhere in the field depressed to any level has a positive predictive value (PPV) of 48% with a negative predictive value of 98.8%. Sensitivity and specificity for the detection of CSME was poor.nnnCONCLUSIONSnThe 20-1 screening program of the FDT is useful in the detection of sight-threatening diabetic retinopathy (PPV 48%). A normal 20-1 test rules out sight-threatening retinopathy. FDT was not useful in the detection of CSME.

Correlation of confocal laser scanning tomography with planimetric photographic measurements of the optic disc in a normal South Indian population: the Vellore Eye Study.

PURPOSEnTo compare the confocal laser tomographic scanning evaluation with photographic measurements of the optic nerve head in a South Indian population.nnnMETHODSnThe prospective comparative clinical non-interventional epidemiologic study included 62 subjects (62 eyes) forming a population-based sample, selected randomly. Mean age was 47.2 +/- 8.9 years, mean refractive error measured was -0.17 +/- 1.10 diopter (range, - 4.50 to + 2.50 diopter). Confocal laser scanning tomographic images on Heidelberg Retina Tomograph (HRT) and colour optic disc photographs were morphometrically analysed and compared. Main outcome measures were morphologic optic disc parameters.nnnRESULTSnThe optic disc area measurements were significantly smaller (p < 0.001) in the HRT technique than in the photographic method. In contrast, the HRT as compared to the photographic measurements showed significantly (p < 0.001) larger values for the relative width and relative area of the neuroretinal rim. The differences in measurements between both methods were maximum in the nasal part (p < 0.001) of the optic disc and minimum in the temporal disc region.nnnCONCLUSIONnIn normal eyes of South Indians, neuroretinal rim measurements by the HRT and expressed as percentage of disc size measurements are significantly larger than rim measurements on disc photographs.

Vitreous opacities in phacolytic glaucoma

BACKGROUND AND OBJECTIVEnTo report five cases of vitreous opacification in phacolytic glaucoma (PG).nnnPATIENTS AND METHODSnThe records of patients with PG were retrospectively reviewed. A total of 135 eyes with PG were studied to determine the presence of vitreous opacification.nnnRESULTSnFive eyes with PG demonstrated opacification of the vitreous, which was first noted at surgery and confirmed postoperatively. All patients had had symptoms of PG for 7 days or more (mean +/- SD, 10.6 +/- 2.4 days) before they sought medical attention. Three eyes had a hypopyon on preoperative examination; two of these eyes showed refractile crystals in the anterior chamber. The opacities resolved spontaneously in all five eyes over a period of 12 weeks and interfered with visual activity only in the immediate postoperative period.nnnCONCLUSIONnVitreous opacification in PG is a self-limited process that may not require surgical intervention unless more rapid visual rehabilitation is desired. The vitreous opacification probably results from an exaggeration of the process causing the anterior chamber reaction.

Ethanolamine oleate sclerotherapy versus simple cyst aspiration in the management of orbitopalpebral cyst associated with congenital microphthalmos.

Purpose: To evaluate the efficacy of ethanolamine oleate (EO) sclerotherapy in the management of orbitopalpebral cysts associated with congenital microphthalmos, and compare it with simple cyst aspiration. Methods: Retrospective, interventional comparative case series of 12 orbitopalpebral cysts of 8 patients associated with congenital microphthalmos. Five cysts were treated with simple aspiration and 7 cysts with EO sclerotherapy. Cyst resolution was the main outcome measure. Results: Five cysts underwent aspiration alone at a median age of 12 weeks. One (20%; 95% CI, 0%–55.1%) of these 5 showed complete resolution. Seven cysts (6 patients) underwent aspiration combined with EO sclerotherapy at a median age of 30 weeks (3 had recurred following prior cyst aspiration). Postsclerotherapy, 6 eyes (85.7%; 95% CI, 59.8%–100%) showed complete cyst resolution (p = 0.072, Fisher exact test). The mean follow-up was 8.8 months (range, 3–23 months). In the EO group, 1 cyst (14.3%) required repeat sclerotherapy and another cyst showed partial resolution at 6 weeks. The number needed to treat with sclerotherapy to prevent 1 recurrence was 2 (1–5, 95% CI). No procedure-related complications were noted. Conclusions: Simple aspiration of orbitopalpebral cyst is associated with a high recurrence rate and should be reserved for early prognostication of visual potential in the microphthalmic eye. Minimally invasive EO sclerotherapy provides a rapid, effective, and uncomplicated treatment modality for definitive therapy, and should be preferred in cases with no visual prognosis in the microphthalmic eye demonstrating adequate bony orbital expansion.

51 – Benefit Versus Risk

Most clinicians intuitively assess benefit versus risk before making management decisions. In more difficult situations, a simple consideration of NNT versus NNH provides direction. Where risks are not readily available from the literature, they can sometimes be calculated using Bayes theorem. In more complicated cases, especially where patient values may make a major difference, the calculation of the ‘likelihood of help versus harm’ (LHH) is a useful way to demonstrate to the patient how their own preferences will direct the management. In really difficult, ‘toss up’ situations, a formal decision analysis may be desirable.

Phacoemulsification-A Senior Surgeon's Learning Curve/COMMENT

We sought to prospectively document and evaluate the learning curve of an experienced extracapsular surgeon making a supervised transition from extracapsular cataract extraction (ECCE) to phacoemulsification. Over a period of 2 weeks, 51 phacoemulsification procedures using an endocapsular nucleofractis technique were performed by a single senior surgeon at the Christian Medical College in Vellore, India under the supervision of a visiting US expert with more than 15 yearsexperience in the technique. Vitreous loss occurred in seven eyes (six prior to the stage of cortical aspiration); failure of capsulorhexis necessitated conversion to standard ECCE in four. Injury to the inferior iris during phacoemulsification was cosmetically significant in three eyes

Anterior Capsular Opacification: Is Aqueous The Culprit?

to maintain good vision and not require a transplant for ten to 15 years, if not more. Of course a transplant could be done whenever it became necessary. Many of the respondents brought up the difficulty of operating on an eye that to the patient has no problems. We do that every time we recommend glaucoma filtering surgery in patients who have no symptomatic visual loss. They have to trust that we are doing for them what is in their longterm best interest. It is also necessary, however, to present the potential complications from surgical intervention, including the severe consequences. That is how I would have approached this patient and I would have definitely exchanged the lens back in 1980. Observation, in such a case, is not a reasonable alternative.