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Artificially-elevated IOP and Corneal Thickness
The central corneal thickness and the applanation IOP was measured in 45 Chinese patients to determine the relation-ship between these 2 parameters. Although no association was found, this could be due to either the limited number of patients with a high IOP (6 subjects had IOP 22 mm Hg), or to the fact that Chinese people have a thicker central cornea. The mean central cornea was 566 ± 36 microns.
30 subjects increased their IOP by adopting a 40 head-down position, after which IOP and topographic corneal thickness were measured again. There was still no significant change in the central corneal thickness. However, the nasal cornea demonstrated a thinning effect during the IOP elevation which returned to normal after the patients returned to a sitting position for a few minutes.
Lam AK; Douthwaite WA. The effect of an artificially-elevated intraocular pressure on corneal thickness in Chinese eye. Ophthalmic Physiol Opt 1997;17:414-420.
Penetrating Keratoplasty for Keratoconus
Keratoconus is a common corneal dys-trophy in which penetrating keratoplasty is an effective form of treatment. 29 patients (32 eyes) with keratoconus who under-went penetrating keratoplasty were enrolled in a study to determine the success of this procedure.
20 patients were followed up post-operatively for 12 months. The visual acuity of 16 (80%) patients improved postoperatively, with 14 (70%) patients having a best corrected visual acuity of 6/12. There were no graft failures.Nine patients (45%) had complications postoperatively. Five patients underwent refractive surgery for correction of astigmatism, although useful vision of 6/60 or better was achieved within 1 week postoperatively in 8 patients (40%).
The authors concluded that penetrating keratoplasty is a successful procedure in keratoconic eyes not correctable by conservative therapy. However, post-operative complications were not un-common and, although the majority were treated successfully, severe com-plications such as retinal detachment and glaucoma were the main causes of poor visual outcome after surgery.
Tay KH, Chan WK. Penetrating keratoplasty for keratoconus. Ann Acad Med Singapore 1997;26:132-137.
Treatment of Full-thickness Macular Holes With Autologous Serum
28 patients (29 eyes) with stage 2-4 idiopathic full-thickness macular holes were treated with autologous serum 20-30 ml placed over each macular hole followed by injection of 16% perfluoro-propane gas. Postoperatively, 28 eyes (97%) had flattening of the macular hole, and the hole could not be detected in 27 eyes (93%). 22 eyes (76%) showed visual acuity improvement by 2 lines. Preoperative factors such as good visual acuity, earlier stage, and younger age were correlated with good postoperative visual acuity. These results suggest that autologous serum is beneficial in the treatment of full-thickness macular holes.
Kusaka S, Sakagami K, Kutsuna M, et al. Treatment of full-thickness macular holes with autologous serum. Jpn J Ophthalmol 1997;41:332-338.
Ultrasound Biomicroscopic Findings After PPT
In order to investigate ultrasound bio-microscopic findings in eyes with shallow anterior chamber and risk of anterior chamber angle closure glaucoma after the prone provocation test (PPT), 32 patients (64 eyes) underwent the PPT in a lighted room. Before and immediately after measurement of intraocular pressure (IOP), high-frequency ultrasound bio-microscopy was performed in the hori-zontal and vertical directions, and chamber angle views were recorded.
10 eyes in 6 patients exhibited an increase in IOP of 8 mm Hg and the profile of the iris showed a markedly convex shape with a large space behind the posterior iris in these patients. The anterior chamber angle of each eye remained open, even during the high level of IOP caused by the provocation. These results suggest that no angle closure occurs during the initial increase of IOP after the PPT. A time lag was observed between the high IOP caused by the pupillary block and the occurrence of angle closure.
Kondo T, Miyazawa D, Unigame K, et al. Ultrasound biomicroscopic findings in humans with shallow anterior chamber and increased intraocular pressure after the prone provocation test. Am J Ophthalmol 1997;124:632-640.
 
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NeoVascular Glaucoma After Cataract Surgery
Kwok et al. performed a retrospective study to evaluate the effect of cataract surgery and postoperative panretinal photocoagulation (PRP) on the develop-ment of neovascular glaucoma (NVG) in heavily irradiated eyes. Patients (90 eyes) received megavoltage external beam irradiation at a retinal dose of 56 to 80 Gy and either cataract surgery or PRP was performed.
The incidence of NVG was significantly higher in patients who underwent cataract surgery without postoperative PRP (p < 0.01) NVG did not develop in any patient receiving both cataract surgery and PRP. These authors concluded that cataract surgery may accelerate the development of NVG in heavily irradiated eyes.
Kwok SK, Leung SF, Ho PC, et al. Neovascular glaucoma developing after uncomplicated cataract surgery for heavily irradiated eyes. Ophthalmology 1997;104:111
Suture Fixation of PC IOL
In order to evaluate the effect of suture fixation of a posterior chamber intraocular lens (PC IOL) on the corneal endothelium, central corneal endothelial cell density was measured in 40 eyes that had planned extracapsular cataract extraction (P-ECCE) with PC IOL implantation and in 40 eyes that had PC IOL implantation by suture fixation. There was no statistically significant difference in central corneal endothelial cell loss between the eyes that had PC IOL implantation by suture fixation and those that had P-ECCE with PC IOL implantation. These authors concluded that PC IOL implantation by suture fixation is a useful and safe method for patients who are aphakic or whose posterior capsule ruptures during cataract surgery.
Lee JH, Oh SY. Corneal endothelial cell loss from suture fixation of a posterior chamber intraocular lens. J Cataract Refract Surg 1997;23:1020-1022.
Physical Fitness and IOP
A study to ascertain the effects of physical fitness on IOP has found that a 3-month supervised exercise programme reduces IOP. IOP was found to be lower in those who did moderate or severe exercise compared with the sedentary control group. The difference between groups was 0.13 ± 0.27 mm Hg (p > 0.05) at baseline, while the difference increased to 0.93 ± 0.28 mm Hg (p < 0.01) after 3 months. The author concludes that physical fitness reduces IOP and recommend that patients who have glaucoma should be encouraged to participate in gentle exercise.
Qureshi IA. Does physical fitness influence intraocular pressure? J Pak Med Assoc 1997;47:81-84.
Perfluoropropane and Trabeculectomy in Young People
The effect of subconjunctival retention of perfluoropropane (C3F8) gas on trabecu-lectomy has been evaluated to determine if this strategy increases the success rate of the surgery. 32 young patients with a diagnosis of primary open angle glaucoma or steroid-induced glaucoma were ran-domised to receive either trabeculectomy alone (group A) or trabeculectomy with subconjunctival retention of 0.5 ml C3F8 gas (group B).
These authors found that the typical appearance of a subconjunctivally retained C3F8 filtering bleb is highly distended in the first 2 weeks after surgery, but gradually flattens and diffuses. The average retention time of C3F8 gas within the subconjunctival space was 28 ± 6 days. A higher success rate was noted in group B than in group A (94% vs 50%; p = 0.016) after 12 months. However, there were no differences in complication rates and results of final visual acuity. These results suggest that subconjunctival retention of C3F8 gas increases the success rate of trabeculectomy in young people in the intermediate follow-up period.
Lu DW, Tai MC, Chiang CH. Subconjunctival retention of C3F8 gas increased the success rates of trabeculectomy in young people. J Ocul Pharmacol Ther 1997;13:235-242.
Cataract-related Blindness in India and its Social Implications
The prevalence of blindness in India is 14.9 per 1000, 80% of which is due to cataract alone. Most cataract blindness is found in rural areas, while the surgical delivery network is concentrated in the urban areas. Thus a large proportion of these patients remain blind.
There are many social implications such as loss of productivity, breakdown of interpersonal relationships, depression, loss of self esteem and the prospect of leading an isolated, humiliating life. Patients lack information on the available services and remain blind even if their condition is operable. This is unfortunate as cataract surgery is one of the most cost-effective health interventions and most patients who undergo surgery are immensely satisfied with the level of visual rehabilitation.
Angra SK, Murthy GV, Gupta SK, et al. Cataract related blindness in India & its social implications. Indian J Med Res 1997;106:312-324.
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